The present invention relates to prestressed beams and more particularly to a novel structure of a multi-axis prestressed double-tee beam and method for construction which includes a cantilever type and a simple-support type and exerts multi-directional prestresses from along a longitudinal, horizontal and vertical orientations.
To construct a bridge is to build up piers of predetermined span at first and then is to prepare the beams which build over the piers therebetween. Finally, the concrete slab is paved on the beams to carry the traffic load. FIG. 1 shows a cantilever beam, at two ends of which the deflection is normally greater than that at middle portion of the beam. FIG. 2 shows a simple-support beam which is contrary to the cantilever beam because the deflection at middle portion of which is greater than that at two ends and the deflection will become more greater upon the increasing of the traffic load. However, if a multi-axis prestressed beam is provided on the bridge, the above deflections will be obviated or offset. Furthermore, the multi-axis prestressed beam is possible to elongate span of the bridge to obtain economical construction of a bridge.